Drawing protector



P 1966 A. o. GOENNER 3,273,244

DRAWING PROTECTOR Filed July 15, 1965 ATTORNEYS 5 United States Patent 3,273,244 DRAWWG PROTECTOR Albert 0. Goenner, 9300 Old Georgetown Road, Bethesda, Md. Filed July 15, 1965, Ser. No. 472,090 12 Claims. (Cl. 33-75) This invention relates to a drawing protector. More specifically, the invention relates to drawing protectors which preclude contact between a T-square or other straight edge and pressure-sensitive adhesive tape securing a drawing on a drawing board, and protects the surface of the drawing.

The employment of T -squares and other straight edges with a tape-secured drawing has presented many problems. Frequently, and particularly after extended use, the adhesive side of the tape becomes exposed to the lower surface of the T-square, causing the T-square to adhere to the tape. Continued use of the T-square results in a physical transfer of the adhesive material from the tape to the T-square. After the adhesive material is transferred to the T-square, movement of the T-square effects a further transfer of graphite and other particles from the T-square to the drawing. The above problems are especially acute for detailed drawings, such as architectural and engineering drawings.

As the drawing is prepared, the surface of the drawing accumulates graphite from the pencil and the products of erasing. When the T-square is subsequently moved, these accumulations are transferred to the T-square and distributed over the drawing.

It is therefore an object of this invention to provide a drawing protector which will obviate the above problems.

Another object is to provide a drawing protector which will effectively prevent a T-square from accumulating any foreign matter and simultaneously render the operation of the T-square more facile.

A further object is to provide a drawing protector which is simple in construction and will not interfere with the movement and employment of the T-square or other straight edge.

Still another object is to provide a drawing protector which when used is readily positioned on a drafting board and when not in use may be compactly coiled during storage.

Yet another object is to provide a drawing protector which allows a T-square to be positioned relative to the drawing board, whereby various drafting operations may be performed at the desired position of the T -square.

Other objects and many attendant advantages of the invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

FIGURE 1 is an isometric view of a drafting board and a T-square with drawing protectors positioned therebetween;

FIGURE 2 is an isometric view of one of the drawing protectors;

FIGURE 3 is a sectional view taken along line 33 of FIGURE 1;

FIGURE 4 is a sectional veiw taken along line 44 of FIGURE 3 and illustrating a drawing protector in a raised position with only the weight of the T-square resting thereon;

FIGURE 5 is a sectional view also taken along line 44 of FIGURE 3, illustrating a drawing protector which has been placed in compressed condition by pressure from the hand of a draftsman using the device;

FIGURE 6 is an isometric view of a drawing protector illustrating the said protector in a coiled condition for storage; and

Patented Sept. 20, 1966 FIGURE 7 is a cross sectional view of a modification of the drawing protector, wherein a thin, flexible core is covered with a thin tough coating of Teflon or other material having a low coeflicient of friction.

Referring now to the drawings, FIGURE 1 shows a conventional drafting board generally designated 10 which may be supported by any known support members (not shown). A drawing 12 is positioned within the periphery of the drafting board 10 and attached thereto by strips of pressure-sensitive adhesive tape 14. To prevent the adhesive surfaces of the tapes 14 from contacting the arm of a T-square, drawing protectors 16 and 16' are positioned over each of the pressure-sensitive adhesive strips 14. Thus, one side of the drawing is preferably adhesively attached to the drawing board 10 by adhesive tape 14, and a similar tape is located along the opposite side of the drawing. While in the present drawing the tapes 14 are shown as continuous, it will be understood that suchstrips may be discontinuous if desired, the use of the drawing protectors being the same in either case.

The construction and operation of the drawing protectors 16 and 16 are identical. It will therefore be apparent that the following description of drawing protector 16 also applies to drawing protector 16'. The drawing protectors are preferably fabricated from thin, flexible, metallic or synthetic material preferably approximately two inches wide. The cross-section of the drawing protector is arcuate, and the inherent rigidity of the metal or plastic is such that the protector is capable of maintaining this arcuate configuration against the Weight of a T-square 28-30.

One highly important modification of the invention is shown in FIGURE 7 of the drawings. In this modification, a thin, flexible strip of material is covered with a relatively thin coating 31 of a material, such as Teflon, which has a relatively high degree of toughness but which has a relatively low coeflicient of friction. Thus, a soft, inexpensive material 'such as aluminum, may be used as the flexible base, and the coating prevents damaging wear of the said relatively soft material along with an actual improvement in the operation of the T-square or drawing instrument because of a relatively low coeflicient of friction, in the range of 0.02-0.04. In order to attach the drawing protectors to the drawmg board 10, each end of the protector is providedwith an aperture. An L-shaped hook member 18 is attached to one extremity of the drawing protector by a hollow rivet 20. A similar hollow rivet 22 is positioned within an aperture located adjacent the opposite end of the pro tector. An elastic band, such as a flexible rubber band 24, or a spring, is inserted through the hollow rivet 22, and a similar hollow rivet 25 is located within a second hook member 26. After the drawing 12 is adhesively secured to the drafting board 10 by the tape 14, the drawing protector 16 is positioned over tape 14, and after the hook member 18 is placed against the lower edge of the drafting board, the elastic device 24 is stretched beyond the opposite edge of the drafting board and the second hook member 26 is engaged with the upper edge of the drafting board.

Subsequent adjustment of the drawing protector is readily accomplished by sliding the hook members 18 and 26 along the opposite edges of the drafting board 10. For storing when not in use, the thin gauge of the metal forming the protectors allows the protectors to be rolled into a compact coil. The elastic member 24 is positioned along the periphery of the drawing protector to maintain the compact coiled relation during storage.

FIGURE 4 illustrates the position of the drawing protector 16 in its unstressed condition. When the T-square is used for line drawing purposes, the T-square is forced downwardly by the draftsman, causing the protector to 3 -assume a flat or stressed condition, as shown in FIGURE 5. The thin gauge of the protector 16 allows flexing of the protector from an unstressed position to a stressed position with a minimum of efi-ort. Additionally, when the protector is flexed to its stressed or flattened position,

the T-square arm 28 is not excessively displaced from the drawing.

The T-square is readily displaced to another location by removing the force applied to the T-square above the protectors, thereby causing the protectors to assume their unstressed position. In their unstressed position, the protectors contact the under surface of theT-square arm at the central portion of the protectors. The contact is thus limited to the central portion to reduce the amount of force which is required to move the T-square. In the modification of FIGURE 7, the low coeflicient of friction of the Teflon covering considerably improves the operation of the straight edge.

In addition to preventing the T-square arm 28 from accumulating graphite, adhesive or other foreign matter, the drawing protectors also allow the T-square arm' to be positioned from the drawing to facilitate certain drawing operations. During inking operations, for example, very many pens will blot or run when a drafting instrument contacts the. pen near its point. By positioning the T- square arm away from the drawing, such blotting may be eliminated.

In the modification of FIGURE 7, while Teflon (polytetrafluoroethylene) has been described as the preferred coating material, any of the superpolamides which are relatively tough and have a relatively low coeflicient of friction may be used. Polytetrafluoroethylene is preferred, however, as having the lowest coeflicient of friction of any known solid material, as well as a resistance to adherence of other materials thereto.

Although I have shown and described a specific structure, it is to be clearly understood that the same is merely for purposes of illustration, and that changes and modifications may be made 'by those skilled in the art without departing from the spirit and scope of the invention as claimed.

What is claimed is:

1. A drawing protector adapted for use with a drafting board, comprising a thin, flexible member of predetermined length and attaching means disposed on opposite longitudinal ends thereof, said drawing protector having an arcuate cross-sectional configuration whereby a portion of the drawing protector may be readily flexed from an arcuate disposition to a flat disposition.

2. A drawing protector as set forth in claim 1, wherein the attaching means comprises a hook member attached to one end of the protector, a second hook member, and

' friction.

5. A drawing protector as set forth in claim 4, wherein said coating is Teflon.

6 In combination, a planar support member, a drawing positioned within the periphery of the support member, adhesive tape means contacting said support member and the drawing, at least one resilient drawing protector positloned over the adhesive means, and a drawing instrument located above and supported by said protector, said protector having an arcuate cross-sectional configuratiom.

whereby the protector may be flexed against the adhesive means by applying a force to the drawing instrument.

7. The combination as set forth in claim 6, wherein the inherent rigidity of the drawing protector flexes the protector to an arcuate disposition against the weight of the drawing instrument.

8. The combination as set forth in claim 7, wherein the drawing instrument contacts two spaced drawing protectors.

9. The combination as set forth in claim 6, wherein attachment means are provided at opposed extremities of the drawing protector for securing the protector relative to the support means.

10. The combination as set forth in claim 6, wherein the drawing protector is fabricated from thin gauge metal.

11. The combination of claim 6, wherein the drawing protector is formed of thin gauge, flexible material having a coating thereon of a tough synthetic plastic of a relatively low coefficient of friction.

12. In combination, a drawing board, a drawing positioned within the periphery of the drawing board, adhes1ve tape means fastening said drawing to said drawing board, at least one resilient drawing protector positioned over the adhesive tape means, and a drawing instrument located above and supported by said protector, said protector having an arcuate cross-sectional configuration, whereby the protector may be flexed against the adhesive means with the drawing instrument by applying a force thereto.

No references cited.

LEONARD FORMAN, Primary Examiner. 

1. A DRAWING PROTECTOR ADAPTED FOR USE WITH A DRAFTING BOARD, COMPRISING A THIN, FLEXIBLE MEMBER OF PREDETERMINED LENGTH AND ATTACHING MEANS DISPOSED ON OPPOSITE LONGITUDINAL ENDS THEREOF, SAID DRAWING PROTECTOR HAVING AN ARCUATE CROSS-SECTION CONFIGURATION WHEREBY A PORTION OF THE DRAWING PROTECTOR MAY BE READILY FIXED FROM AN ARCUATE DISPOSITION TO A FLAT DISPOSITION. 